AM Reception
Premium Member
Hey! Look At Me!! I'm a Supporting Member!!
Joined: Aug 2002
Posts: 265
Likes: 0
Rep Power: 0 
Only time i have personally used the AM stations was to try and find sports stations that are broadcasting nfl games, which will be coming very very soon. God i can't wait for something else to be broadcast on sportscenter besides boring old baseball. ok this is off-topic so i will stop now.
Registered!!
iTrader: (18)
Joined: Feb 2004
Posts: 4,209
Likes: 0
From: La Puente (626), California
Rep Power: 313 Your problem is your power antenna!!! Some people dont even know that are cars have powered antenna's. If the power antenna is not powered on you only get FM and no AM trust me it's happened to me!!\
You need to power the Yellow/Green wire in the factory harness in order to get full Radio reception.
You need to power the Yellow/Green wire in the factory harness in order to get full Radio reception.
Registered!!
Joined: Aug 2001
Posts: 190
Likes: 0
From: Phoenix, Arizona, US
Rep Power: 0 Originally posted by WhiteRabbit
a class D amplifier kills your am reception? that seems kind of silly....
how does class D affect AM reception?
a class D amplifier kills your am reception? that seems kind of silly....
how does class D affect AM reception?
Class D amplfiers switch the output from -HV to +HV (as you prolly already know) The output is a PWM waveform at some carrier frequency. Those severe transients produced from the squarewaves creates harmonics of the carrier frequency. These high freqs are radiated out of the amp (now here is the part i'm not positive HOW/WHY) either its radiated thru the air, or maybe the wires connected to the amp which disturbs the AM reception. If the amplifier has a lot of Ferrite beads to reduce this noise, then it may not be an issue. But I do know that RF's BD's will essentially eliminate your AM. I don't know if this is tru for all cases but I know its a prevelant problem that isn't really addressed because like LudlamTheory says "AM still exists?"
As mentioned above, this is not my area of expertise so if you disagree with something written above, i will gladly listen but this is true to the extent of my knowledge. If this answer isn't suffecient for anybody, I can talk to my boss (The VP of Eng here at RFafter 5 hours of him lectureing to me, I can try and decode what he tells me to offer a better explanation.
~Tbone
Thread Starter
Registered!!
Joined: Aug 2003
Posts: 21
Likes: 0
Rep Power: 0 hmm... now i'm gonna have to decide whether to ground or power the antennae. i'll try both i guess.
AM does exist. No, I particularly would never use it. But beng that my dad's Korean... 1480AM happens to be a Korean channel. Then there's your typical news channels that my generation of parents love. haha.
I'm not running any amps as of yet, so that's not the problem - but will keep in mind when I do drop them in.
Thanks for the help guys.
AM does exist. No, I particularly would never use it. But beng that my dad's Korean... 1480AM happens to be a Korean channel. Then there's your typical news channels that my generation of parents love. haha.
I'm not running any amps as of yet, so that's not the problem - but will keep in mind when I do drop them in.
Thanks for the help guys.
Registered!!
iTrader: (2)
Joined: Sep 2002
Posts: 542
Likes: 0
From: Carlsbad, California, US
Rep Power: 0 Originally posted by tbone323
ok, i'm not a RF expert but I will try and explain this the best I can...
Class D amplfiers switch the output from -HV to +HV (as you prolly already know) The output is a PWM waveform at some carrier frequency. Those severe transients produced from the squarewaves creates harmonics of the carrier frequency. These high freqs are radiated out of the amp (now here is the part i'm not positive HOW/WHY) either its radiated thru the air, or maybe the wires connected to the amp which disturbs the AM reception. If the amplifier has a lot of Ferrite beads to reduce this noise, then it may not be an issue. But I do know that RF's BD's will essentially eliminate your AM. I don't know if this is tru for all cases but I know its a prevelant problem that isn't really addressed because like LudlamTheory says "AM still exists?"
As mentioned above, this is not my area of expertise so if you disagree with something written above, i will gladly listen but this is true to the extent of my knowledge. If this answer isn't suffecient for anybody, I can talk to my boss (The VP of Eng here at RFafter 5 hours of him lectureing to me, I can try and decode what he tells me to offer a better explanation.
~Tbone
ok, i'm not a RF expert but I will try and explain this the best I can...
Class D amplfiers switch the output from -HV to +HV (as you prolly already know) The output is a PWM waveform at some carrier frequency. Those severe transients produced from the squarewaves creates harmonics of the carrier frequency. These high freqs are radiated out of the amp (now here is the part i'm not positive HOW/WHY) either its radiated thru the air, or maybe the wires connected to the amp which disturbs the AM reception. If the amplifier has a lot of Ferrite beads to reduce this noise, then it may not be an issue. But I do know that RF's BD's will essentially eliminate your AM. I don't know if this is tru for all cases but I know its a prevelant problem that isn't really addressed because like LudlamTheory says "AM still exists?"
As mentioned above, this is not my area of expertise so if you disagree with something written above, i will gladly listen but this is true to the extent of my knowledge. If this answer isn't suffecient for anybody, I can talk to my boss (The VP of Eng here at RFafter 5 hours of him lectureing to me, I can try and decode what he tells me to offer a better explanation.
~Tbone
Registered!!
Joined: Mar 2002
Posts: 4,344
Likes: 0
From: bay area, california
Rep Power: 337 no, i dont disagree, i jus ttotally didnt know, sounded like an odd pair of things to be related 
i just have one thing i was hoping you could clarify. and that is where does the ferrite bead go, and what is its structure? is it jsut that, a bead made out of ferrite? if so, where do they put them to control the carrier wave harmonics?
i just have one thing i was hoping you could clarify. and that is where does the ferrite bead go, and what is its structure? is it jsut that, a bead made out of ferrite? if so, where do they put them to control the carrier wave harmonics?
Registered!!
Joined: Mar 2002
Posts: 4,344
Likes: 0
From: bay area, california
Rep Power: 337 oo, oo! lemme guess first, i had a thought that i pulled out of my rear end.
do they go around the ouside of the output wires that transmit the carrier frequency and act essentially as a faradyay cage for the harmonics, not allowing any to leave the amplifier?
do they go around the ouside of the output wires that transmit the carrier frequency and act essentially as a faradyay cage for the harmonics, not allowing any to leave the amplifier?
Registered!!
Joined: Aug 2001
Posts: 190
Likes: 0
From: Phoenix, Arizona, US
Rep Power: 0 Originally posted by WhiteRabbit
oo, oo! lemme guess first, i had a thought that i pulled out of my rear end.
do they go around the ouside of the output wires that transmit the carrier frequency and act essentially as a faradyay cage for the harmonics, not allowing any to leave the amplifier?
oo, oo! lemme guess first, i had a thought that i pulled out of my rear end.
do they go around the ouside of the output wires that transmit the carrier frequency and act essentially as a faradyay cage for the harmonics, not allowing any to leave the amplifier?
You prolly have seen them before...they can be used outside of the device on the cables or, more commenly, the ferrite beads are internal.
The prob is they are not cheap and as you ALL know, to companies, its all about the bottom line and if its not cheap, it prolly won;'t be included (unfortunately).
~Tbone
Registered!!
Joined: Aug 2001
Posts: 190
Likes: 0
From: Phoenix, Arizona, US
Rep Power: 0 its not a very interesting topic...
http://www.act1.com/emi_tut.html
this topic is boring me (you prolly won't notice ANY diff) because it blocks RF and EMI signals so you may* get better radio reception, but your audio coming out of your amp wont sound ANY better.
~Tbone
http://www.act1.com/emi_tut.html
this topic is boring me (you prolly won't notice ANY diff) because it blocks RF and EMI signals so you may* get better radio reception, but your audio coming out of your amp wont sound ANY better.
~Tbone
Second Place is the First Loser
iTrader: (1)
Joined: Oct 2001
Posts: 4,469
Likes: 0
From: San Antonio, Texas, US
Rep Power: 343 Originally posted by nohone
Problem's been solved. It was the power antenna wire as was mentioned.
Thanks everyone
Problem's been solved. It was the power antenna wire as was mentioned.
Thanks everyone
Second Place is the First Loser
iTrader: (1)
Joined: Oct 2001
Posts: 4,469
Likes: 0
From: San Antonio, Texas, US
Rep Power: 343 damn it... it didn't work... I tapped into the Yellow/Green wire from the factory harness... and plugged it into the remote turn on wire from my radio... and i still get a shitty static am.... I used one of those crimp on wire thingies... (the one where you put the wire you are tapping from in the long hole, and the recieving wire right next to it and close the little metal thingy and click it shut.. )
Premium Member
Hey! Look At Me!! I'm a Supporting Member!!
Joined: Aug 2002
Posts: 265
Likes: 0
Rep Power: 0 Sorry for digging this post up after 2.5 months, but i just had to solve this problem because i left work last night and was listening to the MNF game at work and i couldn't listen to it in my car because for am all i hear is crap, i get one AM station in my car but none of the ones that play sports. thanks for all that posted with good info, i just need to rip out my HU...again...got i hate doing this, it's such a pain in the **** to me since i got my civic, it was sooooo easy 2 yrs ago when i drove a......well i drove a dodge neon 
but atleast in the neon i could steal/remove a radio in under 15 seconds. i guess thinking about it now i'm glad our civics are harder to get at the HU.
this is just postive proof that the SEARCH FEATURE works, so get searching you noobs, i posted quite a bit on this site last spring but stopped because all the "new" posts just seemed to be about the same old questions that were talked about previously.
ok we can let this thread die now, please nobody reply unless it's good, unlike my post here.
but atleast in the neon i could steal/remove a radio in under 15 seconds. i guess thinking about it now i'm glad our civics are harder to get at the HU.this is just postive proof that the SEARCH FEATURE works, so get searching you noobs, i posted quite a bit on this site last spring but stopped because all the "new" posts just seemed to be about the same old questions that were talked about previously.
ok we can let this thread die now, please nobody reply unless it's good, unlike my post here.
Registered!!
Joined: Sep 2002
Posts: 279
Likes: 0
From: Tampa Bay, Florida, US
Rep Power: 0 I have the same problem with my Alpine 9807. I tried connecting the yellow/green and blue wires with no luck. Can someone explain exactly how to connect the power antenna lead? I called a couple of local places for some info and all I got was a "your car doesn't have a power antenna". I can post a picture of my setup if needed. Thanks.
